Fluid-handling machines frequently require the arrangement of air separators so as to ensure the functioning of the machine itself and/or of a consumer/receiver of the fluid being located downstream thereof. In particular, in medical machines such as extracorporeal blood treatment machines or heart-lung machines that are provided for removing and re-feeding blood as the fluid to be handled from/to a (human) body, it is important to reduce so-called micro-bubbles inside the blood as a side-effect of extracorporeal blood treatment, before the blood is returned into the body.
Thus, at present it is being discussed whether said micro-bubbles have to be classified as being harmful whatsoever. In the current edition of the Standard 60601-2-16, therefore for the first time an upper limit is indicated for micro-bubbles within the blood for reasons of safety.
The development of medical machines handling fluid (blood) consequently has reacted thereto and inter alia methods of detecting micro-bubbles within a bubble size range of from 10-500 μm have been developed on the basis of a pulsed ultrasound Doppler system, for example. As a result, it was found that fluid (blood) removed from and returned to a body is enriched, due to the extracorporeal treatment, with air bubbles which consequently are likewise guided into the patient's body without any alarm being triggered. Micro-bubbles of this type probably might be the cause of minimal embolisms that may strongly damage internal organs.
Therefore, it is a basic attempt in developing fluid-handling medical machines such as extracorporeal blood treatment machines to reduce the number of micro-bubbles returned into a patient's body in order to minimize the risk for the patient.